1. Field of the Invention
The present invention relates to a device and a method for evaluating the deformation of the surface of the skin, in particular of the skin in vivo. More particularly, the invention relates to a device for the profilometry of the human skin, aiming at evaluating the mechanical properties of the dermis, such as its elasticity and its firmness, or the state of the ageing of the skin, by measuring in a simple and fast manner the depth of the creases induced by deformation. This device is, moreover, suitable for evaluating in series the effectiveness of new basic materials and formulations for counteracting the ageing of the skin which are developed in cosmetic or dermo-pharmaceutical laboratories. Thanks to this new device tests of the ageing of the skin can also be performed at the dermatologist or institutes for cosmetic care, without any need for relying on long and complicated procedures.
2. Discussion of the Background
From the Article of M. Assoul et al. "Three dimensional measurement of skin surface topography by triangulation with new laser profilometer" which appeared in the J. of Med. Eng. and Tech., 1994, 18, 11-21, a device is known for evaluating the state of the surface of the skin in vitro, using resin replicas reproduced on the basis of a skin specimen. These replicas are examined by means of an optoelectronic device operating according to the triangulation method. The prior art device for thus evaluating the state of the skin surface on the basis of resin replicas allows accurate results to be obtained but it is not suitable, on the one hand, for an evaluation in series, in particular in vivo, requiring the preparation and evaluation of the replicas by a specialist and, on the other hand, for permitting an evaluation in a short time.
FR-A-2 607 929 describes a system for a one-way mechanical deformation of the human skin, but does not mention the optical processing of the results of this deformation in any way. Moreover, this document is not explicit as regards the type of deformation applied to the skin. Furthermore, this system does not make it possible to adapt an optoelectronic device of the above mentioned kind in a simple manner.